title: Asthma and risk of non-respiratory tract infection: a population-based case-control study.
abstract: OBJECTIVE
  Asthmatics have increased risks of airway-related infections. Little is known about whether this is true for non-airway-related serious infections such as Escherichia coli bloodstream infection (BSI). We assessed whether asthma is associated with a risk of developing community-acquired E coli BSI.
  
  
  METHODS
  The study was designed as a population-based retrospective case-control study.
  
  
  METHODS
  This population-based study was conducted in Olmsted County, Minnesota.
  
  
  METHODS
  The study included 259 all eligible community-acquired E coli BSI cases in Olmsted County, MN between 1998 and 2007 and 259 birthday-matched, gender-matched and residency-matched controls.
  
  
  METHODS
  Only community-acquired E coli BSI cases as the primary outcome was included. Asthma status as an exposure was ascertained by predetermined criteria. An adjusted OR and 95% CI for the association between asthma and risk of community-acquired E coli BSI was calculated using conditional logistic regression.
  
  
  RESULTS
  Of 259 eligible cases, 179 (69%) were women and mean age was 61±22 years. Of the 259 cases 37 (14%) and 16 (6%) of 259 controls had a prior history of asthma (adjusted OR 2.74; 95% CI 1.11 to 6.76; p=0.029). The population attributable risk of asthma for community-acquired E coli BSI was 9%. Although not statistically significant, there was a borderline association between having a history of food allergy and increased risk of community-acquired E coli BSI (6% vs 2%; adjusted OR 3.51; 95% CI 0.94 to 13.11; p=0.062).
  
  
  CONCLUSIONS
  Based on the findings of the current population-based, case-control investigation, a history of asthma may be associated with risk of community-acquired E coli BSI. The impact of asthma on risk of microbial infections may go beyond airways.
authors.affiliation: Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Duk Won
authors.initials: DW
authors.lastname: Bang
authors.forename: Hyeon J
authors.initials: HJ
authors.lastname: Yang
authors.forename: Eell
authors.initials: E
authors.lastname: Ryoo
authors.forename: Majdi N
authors.initials: MN
authors.lastname: Al-Hasan
authors.forename: Brian
authors.initials: B
authors.lastname: Lahr
authors.forename: Larry M
authors.initials: LM
authors.lastname: Baddour
authors.forename: Barbara P
authors.initials: BP
authors.lastname: Yawn
authors.forename: Young J
authors.initials: YJ
authors.lastname: Juhn
keywords: Epidemiology